HAPTIC EXPLORATION IN THE PRESENCE OF VISION

Two experiments addressed initiation of haptic exploration to encode o bject properties when vision is present. Ss compared pairs of objects on designated properties, using only vision or with touch permitted. T ouch initiation, reach, contact, and visual responses were timed. With difficult material judgments, touch occurred frequently and was initi ated faster than the time to respond by vision alone. With geometric j udgments, touch was rarely used and then was initiated at the typical time for a visual response. Imposing a visual preview before allowing touch did not reduce the incidence of touch but did speed its initiati on. Results support a model in which preliminary visual processing qui ckly initiates haptic exploration for material judgments that are visu ally or semantically difficult.